Medical Microbiology Laboratory
(Sample Collection)
Hussein A. Abid
Medical Laboratory Scientist
Member at American Society of Microbiology
Chairman of Iraqi Medical Laboratory Association
Teacher at Middle Technical University
2
SUCCESSFUL LABORATORY INVESTIGATIONS
 Collection of adequate and appropriate specimens.
 Sufficient documentation.
 Biosafety and decontamination.
 Correct packaging and rapid transport (e.g., sample
to be send out for TB culture).
 Timely communication of results.
3
COMMON SPECIMENS
1. Blood
2. Urine
3. Sputum
4. Swabs (Throat, Nasal, Ear, Eye, HVS, Cervical)
5. Stool
6. Pus
7. CSF
4
SPECIMEN COLLECTION (NOTES)
 Must be collected correctly:
 If not, may not grow in culture
 Contaminants may be mistakenly
identified
 Patient may receive incorrect or
harmful therapy
5
SPECIMEN COLLECTION (GUIDELINES)
 Avoid causing harm or
discomfort to patient
 Collect from appropriate site
 Obtain specimen at correct
time
 Use appropriate devices
 Obtain sufficient quantity
of specimen
 Obtain specimen prior to
the start of antimicrobial
therapy
 Label correctly
GENERIC EQUIPMENT REQUIRED
Transport medium
containing swab
Wood sticks Sterile cup
Sterile, disposable gloves Acid Citrate Dextrose (ACD)
tube for blood collection
6
7
WHAT CONTAINERS TO USE?
 Containers must be leak proof
 Unbreakable
 For cultures sterile containers a Must
8
SPECIMEN COLLECTION
 Devices
o Use appropriate collection
device or specimen container
o Sterile swabs – absorbent
material on the tip
 Collection and transporting systems
o Sterile, self-contained
o Transport medium
o Aerobic or anaerobic
9
TRANSPORT MEDIUM
 Transport medium is a safe and an appropriate way of
carrying the clinical specimens from distances (long or
short) for transporting to the lab for examination.
o It allows organisms to survive.
o It does not allow organisms to proliferate.
 Examples:
o For bacteria – Cary Blair
o For viruses – virus transport media (VTM)
10
1. BLOOD COLLECTION (for culture)
 Venous blood (during high peak fever):
 infants: 0.5 – 2 ml
 children: 2 – 5 ml
 adults: 5 – 10 ml
11
1. BLOOD COLLECTION (for culture)
 The goal in blood collection is avoiding
the contamination.
 A scientific approaches and dedicated
staff participating in blood collection will
eliminate contamination.
 Improper handling of syringes increases
chances of contamination.
 Proper areas of disinfection with good
antiseptic solutions eliminate contam-
ination.
12
1. BLOOD COLLECTION (for culture)
Handling and transport
 Collect into blood culture bottles
(broth)
 Request slip must contain relevant
patient information
 Send immediately to laboratory
with request slip
Blood culture bottles
13
2. URINE
Specimen:
 Early morning midstream urine is
obtained aseptically.
 From babies, urine is collected in
sterile plastic bags.
Transport:
 Transport to laboratory within one hour or
 kept at 4 ºC to avoid multiplication of bacteria in urine.
14
2. URINE
Culture:
 Bacterial count is done using calibrated loop of the un-
centrifuged urine on Blood agar, MacConkey agar and
CLED.
15
3. SPUTUM
Collection of specimen:
 Patient is instructed to take a deep
breath and cough up sputum
directly into a wide-mouth sterile
container of 50-100 ml capacity.
 Avoid saliva or postnasal disch-
arge.
 Minimum volume 1 ml.
16
4. SWABS
 A plain cotton wool swab
should be used to collect as
much exudates as possible
from tonsils, posterior
pharyngeal wall and other
area that is inflamed or
bears exudates.
a) Throat swab (posterior pharyngeal swab)
17
4. SWABS
 If cooperated by patient, the
swab should be rubbed with
rotation over one tonsillar area
of the soft palate and uvula, the
other tonsillar area and finally
the posterior pharynx.
a) Throat swab (posterior pharyngeal swab)
Cooperation of the patient and ideal techniques
contributes better results
18
4. SWABS
 Tilt head backwards
 Insert flexible fine-shafted
polyester swab into nostril
and back to nasopharynx
 Leave in place a few seconds
 Withdraw slowly; rotating motion
b) Nasopharyngeal swab
19
4. SWABS
 No drops should have been
used 3 hours prior to taking
the swab.
 Place the swab into the outer
ear and rotate gently once.
c) Ear swab
20
4. SWABS
 It is ideal to pick up the
material with the thin
serum coated swab.
 Clinical material from
Conjunctiva, i.e. from
averted eyelid
 The margin of the eyelid
should be avoided.
d) Eye swab
21
4. SWABS
 After careful cleaning of the
wound site, a swab was taken
from the inner side of the wound
or the area where pus is
accumulated.
 Rotate the swab gently once.
e) Pus swab (from wounds)
22
5. STOOL SAMPLES
 Whenever possible, a specimen
of stool should be collected.
 A rectal swab is unsatisfactory,
unless it is heavily charged and
visibly stained with faeces
collected from rectum, not anus
23
5. STOOL SAMPLES
Collection and transportation
 Freshly passed stool samples should be collected in
sterile container.
 Avoid specimens from a bed pan.
 Transmit the container quickly to laboratory.
 If delay is unavoidable and particularly when the weather
is warm collect the specimens in a container holding
6 ml buffered glycerol saline transport medium.
24
RECTAL SWABS
Advantages
 convenient
 Used for small children, debilitated patients and other
situations where voided stool sample not feasible
Drawbacks
 no macroscopic assessment possible
 less material available
 not recommended for viruses
25
6. PUS SAMPLES
 Aspirate from abscess or wound in a sterile container.
 Pus should always be aspirated, if possible, rather than
collecting a wound swab.
 Should be transported immediately to the laboratory.
26
7. CEREBROSPINAL FLUID (CSF)
Collection is done:
 By Lumbar puncture
 In sterile tubes
 Under aseptic conditions
 By trained physicians only
27
CSF NEEDS A NEW AND STERILE CONTAINER
 Fresh sterile screw capped
container to be used.
 Reused containers, not to
be used, contamination from
the previous specimens
misrepresent the present
specimen.
28
TRANSPORTATION TO LABORATORY
 The collected specimen of CSF to
be dispatched promptly to
Laboratory, delay may cause death
of delicate pathogens,
 e.g., Meningococci and disintegrate
the leukocytes
29
PRESERVATION OF CSF
 It is important when there is
delay in transportation of
specimens to Laboratory
DO NOT keep in refrigerator,
which tends to kill H.
influenza
 If delay is anticipated leave
at room temperature.

Medical Microbiology Laboratory (sample collection)

  • 1.
    Medical Microbiology Laboratory (SampleCollection) Hussein A. Abid Medical Laboratory Scientist Member at American Society of Microbiology Chairman of Iraqi Medical Laboratory Association Teacher at Middle Technical University
  • 2.
    2 SUCCESSFUL LABORATORY INVESTIGATIONS Collection of adequate and appropriate specimens.  Sufficient documentation.  Biosafety and decontamination.  Correct packaging and rapid transport (e.g., sample to be send out for TB culture).  Timely communication of results.
  • 3.
    3 COMMON SPECIMENS 1. Blood 2.Urine 3. Sputum 4. Swabs (Throat, Nasal, Ear, Eye, HVS, Cervical) 5. Stool 6. Pus 7. CSF
  • 4.
    4 SPECIMEN COLLECTION (NOTES) Must be collected correctly:  If not, may not grow in culture  Contaminants may be mistakenly identified  Patient may receive incorrect or harmful therapy
  • 5.
    5 SPECIMEN COLLECTION (GUIDELINES) Avoid causing harm or discomfort to patient  Collect from appropriate site  Obtain specimen at correct time  Use appropriate devices  Obtain sufficient quantity of specimen  Obtain specimen prior to the start of antimicrobial therapy  Label correctly
  • 6.
    GENERIC EQUIPMENT REQUIRED Transportmedium containing swab Wood sticks Sterile cup Sterile, disposable gloves Acid Citrate Dextrose (ACD) tube for blood collection 6
  • 7.
    7 WHAT CONTAINERS TOUSE?  Containers must be leak proof  Unbreakable  For cultures sterile containers a Must
  • 8.
    8 SPECIMEN COLLECTION  Devices oUse appropriate collection device or specimen container o Sterile swabs – absorbent material on the tip  Collection and transporting systems o Sterile, self-contained o Transport medium o Aerobic or anaerobic
  • 9.
    9 TRANSPORT MEDIUM  Transportmedium is a safe and an appropriate way of carrying the clinical specimens from distances (long or short) for transporting to the lab for examination. o It allows organisms to survive. o It does not allow organisms to proliferate.  Examples: o For bacteria – Cary Blair o For viruses – virus transport media (VTM)
  • 10.
    10 1. BLOOD COLLECTION(for culture)  Venous blood (during high peak fever):  infants: 0.5 – 2 ml  children: 2 – 5 ml  adults: 5 – 10 ml
  • 11.
    11 1. BLOOD COLLECTION(for culture)  The goal in blood collection is avoiding the contamination.  A scientific approaches and dedicated staff participating in blood collection will eliminate contamination.  Improper handling of syringes increases chances of contamination.  Proper areas of disinfection with good antiseptic solutions eliminate contam- ination.
  • 12.
    12 1. BLOOD COLLECTION(for culture) Handling and transport  Collect into blood culture bottles (broth)  Request slip must contain relevant patient information  Send immediately to laboratory with request slip Blood culture bottles
  • 13.
    13 2. URINE Specimen:  Earlymorning midstream urine is obtained aseptically.  From babies, urine is collected in sterile plastic bags. Transport:  Transport to laboratory within one hour or  kept at 4 ºC to avoid multiplication of bacteria in urine.
  • 14.
    14 2. URINE Culture:  Bacterialcount is done using calibrated loop of the un- centrifuged urine on Blood agar, MacConkey agar and CLED.
  • 15.
    15 3. SPUTUM Collection ofspecimen:  Patient is instructed to take a deep breath and cough up sputum directly into a wide-mouth sterile container of 50-100 ml capacity.  Avoid saliva or postnasal disch- arge.  Minimum volume 1 ml.
  • 16.
    16 4. SWABS  Aplain cotton wool swab should be used to collect as much exudates as possible from tonsils, posterior pharyngeal wall and other area that is inflamed or bears exudates. a) Throat swab (posterior pharyngeal swab)
  • 17.
    17 4. SWABS  Ifcooperated by patient, the swab should be rubbed with rotation over one tonsillar area of the soft palate and uvula, the other tonsillar area and finally the posterior pharynx. a) Throat swab (posterior pharyngeal swab) Cooperation of the patient and ideal techniques contributes better results
  • 18.
    18 4. SWABS  Tilthead backwards  Insert flexible fine-shafted polyester swab into nostril and back to nasopharynx  Leave in place a few seconds  Withdraw slowly; rotating motion b) Nasopharyngeal swab
  • 19.
    19 4. SWABS  Nodrops should have been used 3 hours prior to taking the swab.  Place the swab into the outer ear and rotate gently once. c) Ear swab
  • 20.
    20 4. SWABS  Itis ideal to pick up the material with the thin serum coated swab.  Clinical material from Conjunctiva, i.e. from averted eyelid  The margin of the eyelid should be avoided. d) Eye swab
  • 21.
    21 4. SWABS  Aftercareful cleaning of the wound site, a swab was taken from the inner side of the wound or the area where pus is accumulated.  Rotate the swab gently once. e) Pus swab (from wounds)
  • 22.
    22 5. STOOL SAMPLES Whenever possible, a specimen of stool should be collected.  A rectal swab is unsatisfactory, unless it is heavily charged and visibly stained with faeces collected from rectum, not anus
  • 23.
    23 5. STOOL SAMPLES Collectionand transportation  Freshly passed stool samples should be collected in sterile container.  Avoid specimens from a bed pan.  Transmit the container quickly to laboratory.  If delay is unavoidable and particularly when the weather is warm collect the specimens in a container holding 6 ml buffered glycerol saline transport medium.
  • 24.
    24 RECTAL SWABS Advantages  convenient Used for small children, debilitated patients and other situations where voided stool sample not feasible Drawbacks  no macroscopic assessment possible  less material available  not recommended for viruses
  • 25.
    25 6. PUS SAMPLES Aspirate from abscess or wound in a sterile container.  Pus should always be aspirated, if possible, rather than collecting a wound swab.  Should be transported immediately to the laboratory.
  • 26.
    26 7. CEREBROSPINAL FLUID(CSF) Collection is done:  By Lumbar puncture  In sterile tubes  Under aseptic conditions  By trained physicians only
  • 27.
    27 CSF NEEDS ANEW AND STERILE CONTAINER  Fresh sterile screw capped container to be used.  Reused containers, not to be used, contamination from the previous specimens misrepresent the present specimen.
  • 28.
    28 TRANSPORTATION TO LABORATORY The collected specimen of CSF to be dispatched promptly to Laboratory, delay may cause death of delicate pathogens,  e.g., Meningococci and disintegrate the leukocytes
  • 29.
    29 PRESERVATION OF CSF It is important when there is delay in transportation of specimens to Laboratory DO NOT keep in refrigerator, which tends to kill H. influenza  If delay is anticipated leave at room temperature.